The promise of nanotechnology for the next generation of lithium-ion batteries (page 3 of 3)

Challenges in Developing Nanoenabled LIBs

Though the LIB technology is about twenty years old now and even with the advent of nanotechnology, it is still a challenge to attain LIBs with optimal combination of energy, reliability, cost and safety22. With regard to the anode materials, lithium suffers from the dentrite-formation (leading to an explosion of the battery), high reactivity, etc. Hence, nanostructures of tin, silicon, etc., are being used as new anode materials.

Fig. 2: Challenges in the development of nano-enabled LIBs.

Various strategies like (i) decreasing the particle size to nano-range (ii) employing hollow nanostructures (iii) making nanocomposites or nanocoatings with carbon and/or inert components, etc., are being used to achieve high capacity and stable cycle-life of electrodes.

However, these approaches reduce the overall energy density of the anode material due to the following reasons: (i) low packing -density of nanosized materials (ii) presence of large voids in the hollow structures (iii) increased weight -percentage of added carbon/or inert components.

Lately, smartly-designed nanoparticle agglomerates in micron size range are proposed to be used to solve the above said technical drawbacks of using nano-enabled anodes and similar strategies can also be applied for designing efficient nano-sized cathode materials 23,24.

Other challenges such as lowering the high fabrication cost due to energy- consuming synthetic processes, avoiding undesired reactions at electrode/electrolyte interface that arise due to the large surface areas of nanomaterials, preventing the formation of agglomerates during the fabrication process, etc., can be overcome by careful selection of the fabrication procedure

Commercialization of Nanoenabled LIBs: Current Scenario

LIBs have already penetrated the consumer electronics market and are now making the move into HEV/EV applications and grid-storage applications. By 2018, global market for LIBs is expected to grow strong and reach $24.2 billion. Unlike before, the industry is ready to develop improved LIBs for diverse and new applications, thanks to the growing knowledge on new materials/technologies.

At present, most of the research efforts to develop advanced electrodes, safe electrolytes, etc., employ nanomaterials/nanotechnology routinely.

As discussed in the previous section, there are number of challenges that are yet to be met to achieve 100% reliability and the merit of using nanomaterials for next generation LIBs. Especially, in the case of LIBs for electric vehicles, which is considered as a golden ticket for the commercialization LIBs, some startup companies like A123, Ener1, etc., announced bankruptcies in the past few years in spite of receiving huge capital investment and producing batteries with exceptional properties. Experts note that this downfall cannot be solely attributed to the new nanotech-enabled LIB technology but also to the issue of replacing internal combustion engine in vehicles 25,26.

At present, LIBs consume the 65% of the total cost of an electric vehicle, and hence in order to be cost-completive with gasoline, LIBs with twice the energy storage of state-of-art LIBs at 30 % of cost are required27. Thus, the successful commercialization of nano-enabled LIBs for all-electric vehicles depends on various factors as mentioned above.

Apart from these automobile applications, nanoenabled LIBs for powering handheld gadgets and for stationary storage applications are more likely to depend on the improvement in the properties of the LIBs, designing of low-cost fabrication procedures (with high-volume production rates) and usage of abundant, low cost, high energy materials.

Conclusion

LIB technology is rapidly emerging as the most advantageous battery chemistry for transportation as well as consumer electronics. Various research efforts on nanotechnology based LIB technology has already led into the production and use of high performance LIBs (Toshiba, A123 Systems, Altair Nano, Next Alternative Inc., etc.) and yet more improvement with respect to the performance, durability and safety aspects, especially for automotive applications are more likely to be achieved in the future.

Acknowledgement

The author would like to thank Dr. Srinivasan Anandan of ARCI for the insightful discussions on the current research trends on LIBs and Dr. C.K. Nisha of CKMNT for her suggestions on enhancing the content of the article.

By I. Sophia Rani, Centre for Knowledge Management of Nanoscience and Technology (CKMNT). The full article has appeared in the April 2014 issue of "Nanotech Insights" and the above article is an abridged and revised version of the same.